For the (intellectually honest) atheist, life is meaningless. Atheists may find individual meaning in certain aspects of their lives (friends, family, success, etc.), but life itself has no meaning if it is a result of random chance. Without a creator, there is no purpose in creation. If creation serves no purpose, it has no meaning. There is no transcendent meaning to anything in this universe. Belief in God brings meaning to life. God created the universe, and He has some ultimate purpose for it. The nature of that purpose is widely debating among religionists, and is not pertinent to this discussion. The mere fact that a purpose exists gives meaning to life.
Life is difficult and full of trials. Friends and family die, we suffer financial hardship, pain and anguish face us at almost every turn. Our happiness depends on confronting this fact and overcoming it. A frame of reference that gives no transcendent meaning to life does not help us in this arena. Believing that life is ultimately meaningful gives believers a stronger position from which to overcome the difficulties of life. Thus, religion helps people be happy. (Incidentally, this is one reason why unhappy religionists are one of the most damaging things to religion. More on that another time.)
Given that religion makes life more bearable and helps us to be happy, I ask what benefits there are to atheism. How does not believing in God make you a better person, or make life easier to bear? If you wonder about the existence of God, why not believe?